Methods of preparing relief images by enzymatic digestion

ABSTRACT

A RECORDING METHOD WHICH COMPRISES FORMING AN IMAGE CORRESPONDING TO THE DIFFERENCES IN THE AMOUNT OF AN ENZYME, THE IMAGE BEING IN CONFORMITY TO AN IMAGE TO BE RECORDED ON A MATERIAL CAPSULE OF REACTING IN THE PRESENCE OF AN ENZYME AND CAUSING THE REACTION OF SAID MATERIAL WITH SAID ENZYME BY UTILIZING THE ENZYME COMPOSING SAID IMAGE, WHEREBY THE IMAGE TO BE RECORDED IS FORMED ON SAID MATERIAL.

United States Patent 3,563,733 METHODS OF PREPARING RELIEF IMAGES BY ENZYMATIC DIGESTION Seiichi Taguchi, Satoru Honjo, and Eiichi Mizuki,

Saitama, Japan, assignors to Fuji Shashin Film Kabushiki Kaislia, Kanagawa, Japan N0 Dram'ng. Filed Jan. 23, 1968, Ser. No. 699,780 Claims priority, application Japan, Jan. 25, 1967, 42/ 4,898 Int. Cl. G03g 13/22 US. Cl. 96--1 6 Claims ABSTRACT OF THE DISCLOSURE A recording method which comprises forming an image corresponding to the difference in the amount of an enzyme, the image being in conformity to an image to be recorded on a material capable of reacting in the presence of an enzyme and causing the reaction of said material with said enzyme by utilizing the enzyme composing said image, whereby the image to be recorded is formed on said material.

BACKGROUND OF THE INVENTION (1) Field of the invention The present invention relates to a novel recording method.

(2) Description of the prior art In order to realize a highly sensitive recording method, it is necessary that the method includes an amplifying step having high efficiency. For example, in a most widely known recording method in which a silver halide is uti lized, a wide amplification is conducted when a latent image formed by light exposure is reduced with a developer. Also in electrophotography or xerography, there is conducted an amplification by the cross-section of toners. Furthermore, in electrolytic electrophotography in which residual photoconductivity is utilized, the reducing current during the life of the residual photoconductivity contributes the amplification. An object of this invention is to provide a recording method in which biochemical amplification is utilized instead of utilizing a conventional chemical or physical amplification or sensitization.

SUMMARY OF THE INVENTION Thus, the recording method of this invention utilizes the image of an enzyme. That is, the present invention relates to a recording method in which an image of an enzyme is formed on a material capable of causing reaction in the presence of an enzyme due to the difference in the amount of the enzyme corresponding to the image to be recorded. The reaction by the enzyme is caused on said material by utilizing the enzyme forming the image to provide the image on the material.

The important advantages of a recording method in which an enzyme is utilized are as follows:

(a) The reaction can be caused under comparatively mild conditions;

(b) Since the enzyme reacts with a material with a high selectivity, the formation of side reactions are few;

(c) An enzyme gives a strong action even in very small amounts;

(d) Since the action of the enzyme is strongly in fluenced by the pH of the system in which the enzyme is present and the like, the faculty of the enzyme can easily grow in pattern form or can easily be weakened; and

(e) An enzyme is weak in its resistance to heat and hence an image can be easily formed thermally.

Patented Feb. 16, 1971 DETAILED DESCRIPTION OF THE INVENTION Typical examples of the formation of the image of an enzyme are shown below. However, other methods than those shown below, which can be easily anticipated by the persons skilled in the art, can, of course, be employed in the present invention.

(A) Additive method (A-l) A method wherein electrostatic latent images are utilized.An electrostatic latent image is formed on a photoconductive insulating layer or on an insulating layer by various known methods and the latent image is developed by using a finely pulverized enzyme as toner particles or powders. There are known many methods of forming latent images. For example, there are (l) the Carlson method in which an insulating layer is uniformly charged and then a latent image is formed by imageexposing or contacting the layer with a conductive electrode; (2) the Kalman method in which a photoconductive layer is image-exposed and then charged, (3) a method in which a photoelectromotive force is utilized; (4) a method in which an image is formed by heat radiation on an insulating layer before or after charging; (5) a method in which an electrode on which an electric potential has been applied is brought into contact with an insulating layer under pressure, and (6) a method in which the recording surface of an insulating material is scanned by light or an electric potential in conformity with an input signal to be recorded. Furthermore, it is possible to utilize the change in electric properties in response to pressure.

Further, any development method which has been usually employed in the field of electrophotography may be employed to convert an electrostatic latent image into a pattern of enzyme. In particular, in the case of forming images having fine particles, it is desirable to employ a liquid developing method or powder cloud developing method.

(A-2) Hand writing and other methods.An enzyme image may, of course, be formed by direct writing and the like.

(B) Substractive method (B1) A method in which electrostatic latent images are utilized.A toner image is formed on a recording material on the surface of which an enzyme is uniformly placed, whereby the transfer of the enzyme at the portions bearing the toner image to other transferring material is prevented. The various methods shown in (A-1) method can be employed. An enzyme shows a very strong action even in a very small amount, and, hence, when it is incorporated in a photoconductive insulating layer, it usually has an adverse effect on the insulating layer. A more general method is one in which a toner image is transferred onto a recording material having a layer of an enzyme dispersed or dissolved in a suitable binder. The latter process includes a transferring step.

In the method, instead of using the usual toner, a pH adjusting agent may be used as a toner for utilizing the influence of the difference in pH on the activity of enzyme. Also, a material capable of checking the action of enzyme may be used as a toner.

(B-2) Thermal copying method.A recording material containing an enzyme and capable of transmitting infrared rays is superimposed on an original having an image showing a difference in absorption properties to infrared rays and is subjected to a transmittance or reflection exposure. In this way the portions of the material corresponding to the portions having infrared absorbing properties are heated to a high temperature to destroy the enzyme activity and therefore to provide an image. Further, it is possible to cause the change of the properties of the binder such that the enzyme at the heated area is inactivated. Also, if necessary, the pH of the heated areas may be varied. In practicing this method, a recording material is prepared including an enzyme in a material which reacts with the enzyme under a suitable pH. The pH of the recording material is so adjusted that the enzyme is in an inactivated state. If an image having a suitable pH is obtained by the action of heat, the material at the image portions is decomposed or denatured.

In another method, a layer of a heat softenable material is brought into contact with a layer containing an enzyme and they are exposed to infrared rays through an image-bearing original to cause an imagewise transfer of the heat softenable material to the layer of enzyme in conformity with the image said material serving to prevent the enzymes transfer onto another transferring material similar to the aforesaid toner image.

(B3) a method in which a laser, electron beam, or electric discharge is utilizedAn enzyme-containing layer is scanned by a spot of radiation, the strength of which is varied according to the input signal to be recorded to cause the destruction or denaturation of the enzyme or a change in the atmosphere of the enzyme.

(B-4) Direct writing.-An image for preventing the transfer of the enzyme layer may be formed by direct writing. Of course the image may be formed by scanning.

The patterns of the enzyme may be utilized very widely and the enzyme pattern exhibits a catalytic action. Hence, it is not substantially consumed, which makes it possible to use the enzyme image repeatedly. Thus, it may be used as a master for making many reproductions. Also, the pattern of enzyme is used as a matter for converting an image of one material into other materials.

The process of this invention will be explained below.

An enzyme image is formed by the aforesaid method and after transferring the image onto the surface of a uniform gelating layer or conducting the proteolysis of the enzyme immediately by heating and wetting, the gela tin layer is washed off by warm water to provide a relief image. Thereafter, by utilizing the relief image, color photographs or prints can be obtained by various known methods. The excellent point of the method of forming the relief image of gelatin by the method of this invention will become clear by comparing a typical conventional method, such as dye transfer method.

That is, by the method of this invention, high sensitivity can be obtained without using an expensive silver compound. This is because an amplification of 10 to times is conducted in the preparation of an enzyme image, for example, by an electrophotographic process and also the amplification of 10 to 10 times is conducted in the subsequent catalytic action of the enzyme, which causes the amplification of 10 to 10 throughout the whole system.

Further, a strong gelatin layer may be formed by using a hardening agent. In a conventional dye transfer method, the use of a hardening agent in a silver halide emulsion is inhibited until the formation of a relief image, since the selectivity of the tanning action is reduced in the subsequent tanning development step. Therefore, the gelatin layer is weak in strength and the layer must be treated very carefully. Also, the possibility of using it repeatedly is very low. On the other hand, by the process of this invention, a well known hardening agent such as postassium alum may be used without having any adverse influence as well as increasing the sharpness of the image.

Besides the aforesaid two advantages, the process of this invention has such merit that the property capable of reproducing a continuous tone without using a halftone screen can be maintained.

The invention will further be explained by the following examples.

4 EXAMPLE 1 By the action of ultrasonic waves, 02 part by weight of a proteolytic enzyme, proteinase was dispersed in 100 parts by weight of kerosene and an electrostatic latent image formed on an electrophotographic light sensitive paper was developed by using the dispersion thus prepared as a liquid developer. The fine particles of proteinase had been positively charged in kerosene and attached to the negative latent image. The image of proteinase thus formed, was transferred into a wet gelatin surface by press contacting and then the assembly was maintained at 40 C. under a relative humidity of to form a gelatin relief after five minutes. The gelatin relief thus formed could be used as a dye transfer matrix.

EXAMPLE 2 A mixture of parts by weight of photoconductive zinc oxide, 40 parts by weight of a low polymerization silicon resin varnish (non-volatile content 50%, xylene solvent), 10 parts by weight of polyvinyl acetate varnish (non-volatile content 50%, ethyl acetate solvent), 0.5 part by weight of proteinase (proteolytic enzyme), and a proper amount of toluene was kneaded in a porcelain mill and applied to a subbed thick paper in a dry thickness of 10 microns. After drying, the photoconductive light sensitive paper was subjected to corona discharge and then exposed to light through a negative original to form a latent image. Thereafter, the latent image was developed by a cascade developer consisting of a toner and glass particles coated with nitrocellulose and used in a Xerox 914, an electrophotographic apparatus made by the Xerox Co. Since the toner in this combination was negatively charged, an optically negative toner image, the same as the image of the original, was obtained. The toner image was then fixed. Then, a triacetyl cellulose film bearing a hardened gelatin layer thereon and wetted with water was superposed on the toner-bearing layer under pressure. The proteinase was dissolved into water to decompose the corresponding gelatin layer, whereby a gelatin relief was formed.

EXAMPLE 3 Proteinase and polyvinyl alcohol (5:1000) was dispersed in water and the dispersion was applied to a glass plate and dried giving a dry thickness of 5 microns. The light sensitive plate was image-exposed for 8 minutes to a xenon lamp of 200 watts at a distance of 20 cm. therefrom and the layer thus formed was contacted with a gelatin layer while presenting water between the two layers to conduct the decomposition reaction of gelatin by proteinase. Thereafter, by washing the gelatin layer with warm water, a relief layer was obtained.

EXAMPLE 4 A glass plate having a gelatin layer of 8 microns in thickness was immersed in an aqueous 0.2% proteinase solution for 30 seconds and dried by cold and low-humidity blast of 3 C. By processing the gelatin layer thus sensitized by proteinase as in the aforesaid method, a relief image was obtained.

In the case of conducting direct photodecomposition by enzyme, it is well known to spectrally sensitize the system by using a sensitizing dye such as methylene blue or ribofiavine. Therefore, such a spectral sensitization can be also utilized in the method of this invention.

What we claim is:

1. A method of producing a relief image which comprises:

uniformly charging a photoconductive insulating layer of an electrophotographic light-sensitive element; exposing said charged layer to a light image to form a latent electrostatic image;

developing said latent image with an electroscopic parti cle containing a proteolitic enzyme; and

contacting the developed image with a thin layer of a natural polypeptide in the presence of water so as to form a relief image by the imagewise hydrolysis of said polypeptide.

2. The method of claim 1 wherein said natural polypeptide is selected from the group consisting of gelatin and hardened gelatin.

3. A method of producing a relief image which comprises:

forming a layer uniformly containing a proteolitic enzyme;

exposing said layer to imagewise active radiation to form a latent image in said layer; and

contacting the layer with a thin layer of a natural polypeptide in the presence of water so as to form a relief image by the imagewise hydrolysis of said polypeptide.

4. The method of claim 3 wherein said natural polypeptide is selected from the group consisting of gelatin and hardened gelatin.

5. An electrophotographic method of producing a relief image which comprises:

forming a toner image on a layer which uniformly contains a proteolitic enzyme, said toner image preventing the dissolution of said enzyme out of said References Cited UNITED STATES PATENTS 2,965,484 12/1960 Tulagin et a1 9655 3,357,830 12/1967 Bixley 96--l.2

OTHER REFERENCES The Electron Microscopy of Photographic Grains, Etc, by Hamm et al. in J. App. Phys., vol. 24, No. 12, December 1953, pp. 1495-1504.

GEORGE F. LESMES, Primary Examiner J. C. COOPER III, Assistant Examiner US. Cl. X.R. 

